* Chainey.cs: Fix a bug and add tools/output for diagnostics.

* Database.cs: More documentation, more methods for dealing with Word
  Count and Sentence Rarity, better handling of the MaxWords field and
  bugfixing. Also slightly modify the inner workings of sentence
  building.
* Chainey.cs: Rewrite EmitSentence so that diagnostics are always
  written, not just when it succesfully builds a sentence with a seed.

* Database.cs: Simplify the SQL to insert a chain and follow up.
Refactoring of Chainey, moving a lot of stuff out of the IRC specific class and into a more generalized one (BrainFrontend).
Removing unused methods.
Add the option of specifying a comparer.